Prexjentive Measures
Effect of socioeconomic factors on the observed caries reduction after fluoride tablet a n d fluoride toothpaste consumption T . T1JM.STRA*, M . BRINKMAN-ENOELS'^'^ AND A. ^Institute **Caries
oj Sociology, Department oj Medical Sociology, Groningen, and Research Unit, Health Orgattizaliott TNO, Utrecht, the Netherlands
Ttjtitslra, T., Britikuiati-Etigels, M. & Groetieveld, A.: Effect of socioeconotnic factors oti the observed caries rodticliou after fluoride lablet atid fittoride (oolhpastc consuinptiou. Cotiniutnily Dent. Oral Epidetniol. 1978: 6: 227-230. Abstract - The caries experietice of 123 fluoride users (F-tahlets atid/or F^toothpaste) was compared with that of a group of 226 non-users. Fluoride users appeared to have a 15 % lower DFS score (16.2) (Itati non-usets (19.0). After a ttiatchitig jn'occdure had been used to correct for some iutcrvetiing variables (socioecotiotiiic status, toothbrushing habit, .sweet consuuii)tioti) tio difference was found between the groups of F^tablet and F^toolhpaste users and the resi;iective groups of matched non-users. The differetice iu caries experience of 15 % between users and non-users retnaitied in only one group after the niatchitig procedure, that iti wliich the children used both F'tablets and F~tootlipaste. Keywords: detital caries: dentifrice; fluorides; socioeconotny. A. Groetieveld, Caries Research Unit, Health Organizalion TNO, Catharijnesingel 59, Utrecht, the Netherlands (Accepted for public;alion 30 Jnne 1978)
Although niimerou.s studies have shown tlic beneficial effects of water fhioridation, most countries in Western Europe have not implemented this excellent public health measure. It is understandable, therefore, that in these countries preventive dentistry is focused on alternative fluoride delivery systems for the reduction of dental caries. T h e administration of fluoride tablets is one of the best known methods. A number of investigations (1, 2, 4, 9, 13) into the cariostatic effect of fluoride tablets have demonstrated a wide range of caries reductions (5, 7, 8, 14). It appears from these studies that a number of factors may bias the results. Many studies lack statistical analyses, almost all have no placebo group, others were completed by only one investigator (9) or 'were carried out on groups preselected for aboveaverage dental behavior. A major problem, however, seems to be lack of
interest at the start of tlie experiments and the loss of a number of individuals during the sttidy (2, 10), leading to the selection of the dentally motivated in the experimental group. It is possible that when the experiments were completed the experimental groups consisted solely of children highly selected towards good dental health behavior. It can be concluded that the children in the experimental groups, who were able to follow the strict regimen of tablet consumption for several years, may also have been equally conscientious with regard to "favorable eating and cleaning habits" (1). The children who use fluoride tablets are thus perliaps the children who need them least of all. If so, the administration of fhioride tablets is not directly suitable as a caries-reducing measure in public health programs (12). Another problem is of a psychologic nature. Parents or guardians who distribute fhioride tablets are
228
TijMSTRA, Bt^INKMAN-ENC,ta.S AND GtlOt'.NEVELD
investing time and care in dental health and thc daily nsc of tablets i.s a constant reminder of its value. It is po.ssible tliat these two phenomena alone lead to better dental health beliavior. Thi.s may lead to a reduction in the caries increment quite apart from thc effect of thc fhioride in the tablets. These psychological factors are not eliminated even in experiments using a placebo group (6, 8 ) . The aim of this study was to investigate the real effect of fluoride in fluoride tablets. This was achieved by using a matching procedure to correct for sotne intervening variables, e.g. socioeconotnic status, toothbrushing and sweet consiiinption.
MATERIAL AND Ml^THODS The .siudy was carried out in I97(i on .583 niiidonily scIcclcd .school children in Lcciiwarden, a non-fluoridaled lown in llic norlh of llie Netherlands. All children vvere born in 1961. Exaininalions were completed on 269 boys and 314 girls. Pils, fissures and free sinoolh surfa(es were examined cliuically while a|)|:iroxinial surfaces were seored from bilewiug radio,a;raphs, using a slandardized techuiciuc (3). Clinical examiiialions uere carried out by llirec dentisis, using a mirror, jMobe, compressed air aud uioulhlauip. Approximately one in every 10 children was examined tti dujilo in order to maintain interexaminer agreemeni aud avoid a sliifl in diagnostie .standards. The DFS-index was calculated for (-ach child. Adjuslmenls were made both for exiracled (eetli whicli were eonsidered to be equal to two caries units and for orthodontic extraclions. The ehildren were asked to fill in a ]H'eeoded c|uestionnaire, before their dental examination, to oblain information about their denial health behavior (toothbrusliiug, sweet eonsumption). Their mothers were also interviewed at a later dale and dala were collected about their denial behavior, attitudes and knowledge. Some structural family variables such as cducalion, income and occujxitiou of both jxnents were also recorded. In all, 9.5 % of Ihc children and 94 % of their mothers took part iu these investigalions. Queslions aboul the use of fluorides were an.swered by the mothers. These were formulated as follows: Has your child taken fluoride tablets aud if so for how long? Ha.s your child used fluoridated toothpaste and if .so for how long? This article is based ou the answers to these two questions. This ii)ean.s that no informal ion is available about the delivery .system, F-couceiitration, daily dose, whether chewed or swallowed, etc. MATCI-ONG PROCEDURE A comparison between fluoride users and non-users showed that these groups differed from each other with regard to some structural variables. Families of F-users had a iiigher
Table 1. Caries experienee of users and nou-nseis of fluoride tablets and/or F-eontaining loolhinisle
Non-users Users All ehildren
Caries experience mean Dl'S
No. of ehikhen
19.0 I (i.2 18..')
226 123 583
Sludent's t-test; i = 2.17; P < 0 . 0 2 5 .
ineome, were better educated and had a higher occupalioual status. There were also some differenees in dental health behavior: the coiisuiuptioii of sweels was somewhat lower and oral hygiene habils slightly belter in ihe group ol I'-iisers. As these variables are also correlated to dental slatus, their effects on Vhe results should, if jxxssible, be eliminaled. Sinee Ihe number of F-users was relatively small in comparison witli the non-users, a inateliing procedure was used. This consisted of the following: firstly, only those children who had used fluoride for at least 2 years and were still using it at ihe lime of ihe investigation, were included iu this study. Secondly, eaeh fluoride user was inalched with a non-u.ser with regard lo occu]nitional status of the lather, toothbrusliiug and sweet eonsumptiou.
RESULTS Fluoride tablets - sixty percent of all mothers stated that their child had never used any F-tablets. Only 13 % 'were using F-lablets at tlic time of the investigation. The mean number of years that the children had used tliese F-taljlets was 6.9; 25 % of the children had previously taken F-tablets for a mean of 4 years; 1 % of tlie children had used F-tablets oceasionally. Fluoride toolhpasle - At the time of the investigation 26 % of the children were using a fluoridated toothpaste and had used it for a mean of 3 years, 60 % had never used an F-containing
'Fable 2. Caries experience of three groups of fluoride
Mean uo. of years Non-users, F-tablels F'-looth paste F-tablels + F-loolhpasle
8.2 4.3 7.7 .5.1
Caries experienee mean DF,S
No. of children
19.0 16.6 17.5
226 49 40
14.2
34
Fhioride tablets and socioecononiic factors T a b l e 3. Caries cx|3cri('nrc ol ihrcc groups of fluoride uscr.s and three group.s of male lied nou-users Cai ies e.xpci iciiee
mean Dl'S Non-users F-tablet.s users m a t c b c d iion-i\sers F-tootlipas(c users m a t c h e d non-users F-tablet.s + F-lc)()llipasle users m a t c h e d uon-users
19.0 1 6.6 15.7 17.5 17.6 14.2 I ().9
lablc 4. Caries experieuee of user.s and uou-users and Ihe lualihed group Caries experience mean Dl'S
No. of eliildrcn 226 49 49 40 4-0 34 34
toothpaste, 5 ''/c had used F-toothpaste in the past ( m e a n of 1.6 years) and 8 7r »scd it occasionally. Fluoride lablels + fluoride loolhpitslc - Fortytwo percent of the uiothers answered that their child had used neither F-tablets nor l''-tootlipaste. Seven, percent of the children were using both Ftablets and F-toothpaste at the time of the investigation. Cartes experience - Table 1 shows tbe DFS .scores for the various groups. The mean DFS score of all 58.S children was 18,5, The 226 children who h a d never used any fluoride had a mean caries experience of 19.0. The 123 fluoride users had a DFS score which was significantly lower than that of the non-users. M o r e detailed information about the eflect of the different types of fluoride supplementation is given in T a b l e 2. The 49 children who had used fluoride tablets for a mean period of over 8 years had a DFS score of 16.6. T h e 40 F-tootbpastc users had a score of 17.5, which 'was also somewhat lower than that of the non-users group. The users of bolb tablets and toothpaste bad the lowest DFS score of all. RE.SULTS AFTKR THE MATCFIING I'ROCEDURF. In cjrder to obtain the most reliable information the children in the three groups of fluoride users (49 children in tbe F-tablet group, 40 in the F-tootlipaste group and 34 in the F-tablet + F-toothpa.ste group) were matched with tbe same number ol children, from the non-users group matched with the same nutnber of children from the lion-tiset's group according to tbe variables: occupation ol ibe father, sweet consumption and toothbrushing habits. T a b l e 3 shows the caries experience in the diller-
229
Non-users Users MaleUed no\i-users
19.0 16.7
No. of ehildreu 226 123 123
ent groups after tbe matching procedure. 'Fhe 49 children using fluoride tablets had a slightly lower caries experience than the non-users. But it appears that the 49 ittaUhcd non-users also bad a lower caries experience than the non-users. This result is al.so .seen in the fluoride toothpa.ste group. Only in the group of 34 u.sei's of both F-tablets and F-toothpaste was there a difference between users and matched non-users, aUbough the eifect of the matching procedure can also be obsei'\'ed here. This may demonstrate the adx-antage of a multiple fluoride therapy. When all the fhioride users are considered as one group a comparison can be made with 1 able 1. The result is shown in Table 4; the matched nonusers \rc\\c a lower caries experience which is eomparable to that of the F-lablets users.
DISCUSSION This study shows, as have other epidemiologic studies (7, 11), that fluoride supplementation results in a lower caries experience. Howes-ev, a more detailed analy.sis of the results indicates that this reduction is caused by other factors. It may not be directly concluded from this investigation that F-lablets or F-toothpaste are ineffective. 'Fhe po.ssibility remains that children with poor dental health may also preferentially use fluoride supplementation. This means that F-usevs would ha\'e bad a higher DFS score without the use of F-supplementatioii. There is, however, no evidence to support this view. Mothers often have no clear picture of their own child's dental health, certainly not w'heii tlie cliild was 7 or 8 )'cars old (when fluoride tablets were first administered; see Table 2 ) . It should be remembered that this lack of effect of fluorides was assessed in a group of relatively old, 14-13 years, children. The mean number of vears
230
TiJMSTRA, BRINKMAN-ENGtCLS AND Gt^OtiNEVEt.D
that the children had cotisumcd F-tablefs was about 8 years, thus the preeruplivc effect of fluoride svipplcmcntation on premolars and second molars was included. There still reniains the possibility that fluoride it! this form lias a temporary effect on tlic pcrlTiancnt teeth at an earlier age. Its effect on the primary teeth cannot, of cour.sc, be measured in this age group. The results clearly show that a simple comparison between the caries experience of F-users and t\otiusers cannot be used to provide conclusive evidence of a caries reduction. Only iti studies where a placebo group has been used can a reliable estimate of the F-cffcct as such be made, Utifortunatcly, the psychological effect has still not been mca.surcd; a third group is therefore required, but such an experimental design is almost impossible, Socioeconomically the F-users belong lo a relatively highly selected group. Because of this fluoride tablets may be of doubtful value as a public health measure, particularly if their regular use is uiisupervised!
tablets. Results of 13 year observations. Oral Res. Abstr. 1968: 3: 796. 5. Bimn, B. G., "WIEKINS, E . & Wrrcji,, E.: A iJieliniinarv,sludy of the cffecls of fluoride lozcnf>i',s and pills on dental caries. Oral Surg. 1955: H: 213-216. 6. Di,P.,\OEA, P. E. & LAX, M . : The caries inhibiting effect of acidulated phosphate-fluoride diewable tablets: a two-year double blind study. /. Am. Dent. Assoe. 1968: 76"; 554-557. 7. DKI.SCOI.I., "\V, S,: The use of fluoride tablets for the
prevention of dental caries, fn: EORRE.S'I-ER, J. & SciiDEZ, K. M. (ed.): International worksho]) on fluoride and dental caries reductions. Baltimore, Maryland 1974, pp. 2,5-93. 8. DRISCOEL, W . S., HEIEET/., S. B., Koirrs, D. C , MKMJ^S, R, J . & HOROWITZ, H . S.: Effect of acidu-
lated |5hosi)liate fluoride chewahle tablets in school children: Results after 55 months. / . Am. Dent. A.ssoc. 1977: 94: 537-543. 9. HAMIIERCI, L,: Controlled trial of fluoride in vitamin drops for iMeventioii of caries in children. Lancet 1971: /.• 441-442. 10. HI.;NN(),\, D . K . , STOOKI:V, G . K , & MiniEKK, J, C : The
clinical anticariogcnie erfeclivencss of supplementary fluoride-vitamin ])reparations. /. Pharmacol. Thcr. Dent. 1970: / ; 1-6. 11. Por, T., KWANT, G . "W., TIIEIINS, H , M . , PEASSCHAERT, A, J. N,, TRUIN, G . J . & KONIG, K . G . : Ondeiv.oek
REFERENCES 1. AASKNDKN, R , & PKKBI.ES, T . C : Effects of fluoride
sup])Ieiiientation from birth on human deciduous and permanent teeth. Arch. Oral Biol. 19.')4: 19: 321-326, 2. ARNOLD, F . A,, DEAN, H , T . , JAY, P, & KNUI'SON, J.
W.: Effect of fluoridated publie water supplies oti dental caries prevalence tenth year of Grand RapiclsMuskegon study. Public Health Rep. 1956: 71: 652657, 3. BACKER-DIRKS, O . & KWANT, G . W . : A reproducible
method for earies evaluation. Ned. Tijdsclir. Tandheelkd. 19.54: 61: 891-904. 4. Bi-.RNi;Rii, L., FI:KNI:.\-, E . & FIi;i.u, A. J.: A .study on the cariostatic effect of sodium fluoride (Zyniafluor)
naar de gebitsloe.sUind van 6-, 8-, 10- en 12-jarige kiiidercn in Overijssel. Ned. Tijdschr. Tandheelkd. 1976: 83: 290-301, 12. PRKHIAKD, J . E,: The prenatal and irastnatal effeets of fluoride supplements on "West Australian schoolchildren, aged 6", 7 and 8; Perth 1967. Aust. Dent ] 196914: 335-338. 13. STOI.TK, G.: Results of three years of carie.s jjirophylaxis by oral fluoride ap|jlication in Solingen kindergartens, Zahnaerztl. Mitl. 1968: 58; 380-382, 14. STONES, H . H . , EAWTON, F . E , , BRANSUY, E . R . &
HARTLEY, H . O . : T"he effect of to]5ical applications of potassium fluoride and of the ingestion of tablets coiilaining .sodium fluoride on the incidence of dental caries. Br. Dent. ]. 1949: 86; 263-271.
Effect of socioeconomic factors on the observed caries reduction after fluoride tablet a n d fluoride toothpaste consumption T . T1JM.STRA*, M . BRINKMAN-ENOELS'^'^ AND A. ^Institute **Caries
oj Sociology, Department oj Medical Sociology, Groningen, and Research Unit, Health Orgattizaliott TNO, Utrecht, the Netherlands
Ttjtitslra, T., Britikuiati-Etigels, M. & Groetieveld, A.: Effect of socioeconotnic factors oti the observed caries rodticliou after fluoride lablet atid fittoride (oolhpastc consuinptiou. Cotiniutnily Dent. Oral Epidetniol. 1978: 6: 227-230. Abstract - The caries experietice of 123 fluoride users (F-tahlets atid/or F^toothpaste) was compared with that of a group of 226 non-users. Fluoride users appeared to have a 15 % lower DFS score (16.2) (Itati non-usets (19.0). After a ttiatchitig jn'occdure had been used to correct for some iutcrvetiing variables (socioecotiotiiic status, toothbrushing habit, .sweet consuuii)tioti) tio difference was found between the groups of F^tablet and F^toolhpaste users and the resi;iective groups of matched non-users. The differetice iu caries experience of 15 % between users and non-users retnaitied in only one group after the niatchitig procedure, that iti wliich the children used both F'tablets and F~tootlipaste. Keywords: detital caries: dentifrice; fluorides; socioeconotny. A. Groetieveld, Caries Research Unit, Health Organizalion TNO, Catharijnesingel 59, Utrecht, the Netherlands (Accepted for public;alion 30 Jnne 1978)
Although niimerou.s studies have shown tlic beneficial effects of water fhioridation, most countries in Western Europe have not implemented this excellent public health measure. It is understandable, therefore, that in these countries preventive dentistry is focused on alternative fluoride delivery systems for the reduction of dental caries. T h e administration of fluoride tablets is one of the best known methods. A number of investigations (1, 2, 4, 9, 13) into the cariostatic effect of fluoride tablets have demonstrated a wide range of caries reductions (5, 7, 8, 14). It appears from these studies that a number of factors may bias the results. Many studies lack statistical analyses, almost all have no placebo group, others were completed by only one investigator (9) or 'were carried out on groups preselected for aboveaverage dental behavior. A major problem, however, seems to be lack of
interest at the start of tlie experiments and the loss of a number of individuals during the sttidy (2, 10), leading to the selection of the dentally motivated in the experimental group. It is possible that when the experiments were completed the experimental groups consisted solely of children highly selected towards good dental health behavior. It can be concluded that the children in the experimental groups, who were able to follow the strict regimen of tablet consumption for several years, may also have been equally conscientious with regard to "favorable eating and cleaning habits" (1). The children who use fluoride tablets are thus perliaps the children who need them least of all. If so, the administration of fhioride tablets is not directly suitable as a caries-reducing measure in public health programs (12). Another problem is of a psychologic nature. Parents or guardians who distribute fhioride tablets are
228
TijMSTRA, Bt^INKMAN-ENC,ta.S AND GtlOt'.NEVELD
investing time and care in dental health and thc daily nsc of tablets i.s a constant reminder of its value. It is po.ssible tliat these two phenomena alone lead to better dental health beliavior. Thi.s may lead to a reduction in the caries increment quite apart from thc effect of thc fhioride in the tablets. These psychological factors are not eliminated even in experiments using a placebo group (6, 8 ) . The aim of this study was to investigate the real effect of fluoride in fluoride tablets. This was achieved by using a matching procedure to correct for sotne intervening variables, e.g. socioeconotnic status, toothbrushing and sweet consiiinption.
MATERIAL AND Ml^THODS The .siudy was carried out in I97(i on .583 niiidonily scIcclcd .school children in Lcciiwarden, a non-fluoridaled lown in llic norlh of llie Netherlands. All children vvere born in 1961. Exaininalions were completed on 269 boys and 314 girls. Pils, fissures and free sinoolh surfa(es were examined cliuically while a|)|:iroxinial surfaces were seored from bilewiug radio,a;raphs, using a slandardized techuiciuc (3). Clinical examiiialions uere carried out by llirec dentisis, using a mirror, jMobe, compressed air aud uioulhlauip. Approximately one in every 10 children was examined tti dujilo in order to maintain interexaminer agreemeni aud avoid a sliifl in diagnostie .standards. The DFS-index was calculated for (-ach child. Adjuslmenls were made both for exiracled (eetli whicli were eonsidered to be equal to two caries units and for orthodontic extraclions. The ehildren were asked to fill in a ]H'eeoded c|uestionnaire, before their dental examination, to oblain information about their denial health behavior (toothbrusliiug, sweet eonsumption). Their mothers were also interviewed at a later dale and dala were collected about their denial behavior, attitudes and knowledge. Some structural family variables such as cducalion, income and occujxitiou of both jxnents were also recorded. In all, 9.5 % of Ihc children and 94 % of their mothers took part iu these investigalions. Queslions aboul the use of fluorides were an.swered by the mothers. These were formulated as follows: Has your child taken fluoride tablets aud if so for how long? Ha.s your child used fluoridated toothpaste and if .so for how long? This article is based ou the answers to these two questions. This ii)ean.s that no informal ion is available about the delivery .system, F-couceiitration, daily dose, whether chewed or swallowed, etc. MATCI-ONG PROCEDURE A comparison between fluoride users and non-users showed that these groups differed from each other with regard to some structural variables. Families of F-users had a iiigher
Table 1. Caries experienee of users and nou-nseis of fluoride tablets and/or F-eontaining loolhinisle
Non-users Users All ehildren
Caries experience mean Dl'S
No. of ehikhen
19.0 I (i.2 18..')
226 123 583
Sludent's t-test; i = 2.17; P < 0 . 0 2 5 .
ineome, were better educated and had a higher occupalioual status. There were also some differenees in dental health behavior: the coiisuiuptioii of sweels was somewhat lower and oral hygiene habils slightly belter in ihe group ol I'-iisers. As these variables are also correlated to dental slatus, their effects on Vhe results should, if jxxssible, be eliminaled. Sinee Ihe number of F-users was relatively small in comparison witli the non-users, a inateliing procedure was used. This consisted of the following: firstly, only those children who had used fluoride for at least 2 years and were still using it at ihe lime of ihe investigation, were included iu this study. Secondly, eaeh fluoride user was inalched with a non-u.ser with regard lo occu]nitional status of the lather, toothbrusliiug and sweet eonsumptiou.
RESULTS Fluoride tablets - sixty percent of all mothers stated that their child had never used any F-tablets. Only 13 % 'were using F-lablets at tlic time of the investigation. The mean number of years that the children had used tliese F-taljlets was 6.9; 25 % of the children had previously taken F-tablets for a mean of 4 years; 1 % of tlie children had used F-tablets oceasionally. Fluoride toolhpasle - At the time of the investigation 26 % of the children were using a fluoridated toothpaste and had used it for a mean of 3 years, 60 % had never used an F-containing
'Fable 2. Caries experience of three groups of fluoride
Mean uo. of years Non-users, F-tablels F'-looth paste F-tablels + F-loolhpasle
8.2 4.3 7.7 .5.1
Caries experienee mean DF,S
No. of children
19.0 16.6 17.5
226 49 40
14.2
34
Fhioride tablets and socioecononiic factors T a b l e 3. Caries cx|3cri('nrc ol ihrcc groups of fluoride uscr.s and three group.s of male lied nou-users Cai ies e.xpci iciiee
mean Dl'S Non-users F-tablet.s users m a t c b c d iion-i\sers F-tootlipas(c users m a t c h e d non-users F-tablet.s + F-lc)()llipasle users m a t c h e d uon-users
19.0 1 6.6 15.7 17.5 17.6 14.2 I ().9
lablc 4. Caries experieuee of user.s and uou-users and Ihe lualihed group Caries experience mean Dl'S
No. of eliildrcn 226 49 49 40 4-0 34 34
toothpaste, 5 ''/c had used F-toothpaste in the past ( m e a n of 1.6 years) and 8 7r »scd it occasionally. Fluoride lablels + fluoride loolhpitslc - Fortytwo percent of the uiothers answered that their child had used neither F-tablets nor l''-tootlipaste. Seven, percent of the children were using both Ftablets and F-toothpaste at the time of the investigation. Cartes experience - Table 1 shows tbe DFS .scores for the various groups. The mean DFS score of all 58.S children was 18,5, The 226 children who h a d never used any fluoride had a mean caries experience of 19.0. The 123 fluoride users had a DFS score which was significantly lower than that of the non-users. M o r e detailed information about the eflect of the different types of fluoride supplementation is given in T a b l e 2. The 49 children who had used fluoride tablets for a mean period of over 8 years had a DFS score of 16.6. T h e 40 F-tootbpastc users had a score of 17.5, which 'was also somewhat lower than that of the non-users group. The users of bolb tablets and toothpaste bad the lowest DFS score of all. RE.SULTS AFTKR THE MATCFIING I'ROCEDURF. In cjrder to obtain the most reliable information the children in the three groups of fluoride users (49 children in tbe F-tablet group, 40 in the F-tootlipaste group and 34 in the F-tablet + F-toothpa.ste group) were matched with tbe same number ol children, from the non-users group matched with the same nutnber of children from the lion-tiset's group according to tbe variables: occupation ol ibe father, sweet consumption and toothbrushing habits. T a b l e 3 shows the caries experience in the diller-
229
Non-users Users MaleUed no\i-users
19.0 16.7
No. of ehildreu 226 123 123
ent groups after tbe matching procedure. 'Fhe 49 children using fluoride tablets had a slightly lower caries experience than the non-users. But it appears that the 49 ittaUhcd non-users also bad a lower caries experience than the non-users. This result is al.so .seen in the fluoride toothpa.ste group. Only in the group of 34 u.sei's of both F-tablets and F-toothpaste was there a difference between users and matched non-users, aUbough the eifect of the matching procedure can also be obsei'\'ed here. This may demonstrate the adx-antage of a multiple fluoride therapy. When all the fhioride users are considered as one group a comparison can be made with 1 able 1. The result is shown in Table 4; the matched nonusers \rc\\c a lower caries experience which is eomparable to that of the F-lablets users.
DISCUSSION This study shows, as have other epidemiologic studies (7, 11), that fluoride supplementation results in a lower caries experience. Howes-ev, a more detailed analy.sis of the results indicates that this reduction is caused by other factors. It may not be directly concluded from this investigation that F-lablets or F-toothpaste are ineffective. 'Fhe po.ssibility remains that children with poor dental health may also preferentially use fluoride supplementation. This means that F-usevs would ha\'e bad a higher DFS score without the use of F-supplementatioii. There is, however, no evidence to support this view. Mothers often have no clear picture of their own child's dental health, certainly not w'heii tlie cliild was 7 or 8 )'cars old (when fluoride tablets were first administered; see Table 2 ) . It should be remembered that this lack of effect of fluorides was assessed in a group of relatively old, 14-13 years, children. The mean number of vears
230
TiJMSTRA, BRINKMAN-ENGtCLS AND Gt^OtiNEVEt.D
that the children had cotisumcd F-tablefs was about 8 years, thus the preeruplivc effect of fluoride svipplcmcntation on premolars and second molars was included. There still reniains the possibility that fluoride it! this form lias a temporary effect on tlic pcrlTiancnt teeth at an earlier age. Its effect on the primary teeth cannot, of cour.sc, be measured in this age group. The results clearly show that a simple comparison between the caries experience of F-users and t\otiusers cannot be used to provide conclusive evidence of a caries reduction. Only iti studies where a placebo group has been used can a reliable estimate of the F-cffcct as such be made, Utifortunatcly, the psychological effect has still not been mca.surcd; a third group is therefore required, but such an experimental design is almost impossible, Socioeconomically the F-users belong lo a relatively highly selected group. Because of this fluoride tablets may be of doubtful value as a public health measure, particularly if their regular use is uiisupervised!
tablets. Results of 13 year observations. Oral Res. Abstr. 1968: 3: 796. 5. Bimn, B. G., "WIEKINS, E . & Wrrcji,, E.: A iJieliniinarv,sludy of the cffecls of fluoride lozcnf>i',s and pills on dental caries. Oral Surg. 1955: H: 213-216. 6. Di,P.,\OEA, P. E. & LAX, M . : The caries inhibiting effect of acidulated phosphate-fluoride diewable tablets: a two-year double blind study. /. Am. Dent. Assoe. 1968: 76"; 554-557. 7. DKI.SCOI.I., "\V, S,: The use of fluoride tablets for the
prevention of dental caries, fn: EORRE.S'I-ER, J. & SciiDEZ, K. M. (ed.): International worksho]) on fluoride and dental caries reductions. Baltimore, Maryland 1974, pp. 2,5-93. 8. DRISCOEL, W . S., HEIEET/., S. B., Koirrs, D. C , MKMJ^S, R, J . & HOROWITZ, H . S.: Effect of acidu-
lated |5hosi)liate fluoride chewahle tablets in school children: Results after 55 months. / . Am. Dent. A.ssoc. 1977: 94: 537-543. 9. HAMIIERCI, L,: Controlled trial of fluoride in vitamin drops for iMeventioii of caries in children. Lancet 1971: /.• 441-442. 10. HI.;NN(),\, D . K . , STOOKI:V, G . K , & MiniEKK, J, C : The
clinical anticariogcnie erfeclivencss of supplementary fluoride-vitamin ])reparations. /. Pharmacol. Thcr. Dent. 1970: / ; 1-6. 11. Por, T., KWANT, G . "W., TIIEIINS, H , M . , PEASSCHAERT, A, J. N,, TRUIN, G . J . & KONIG, K . G . : Ondeiv.oek
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W.: Effect of fluoridated publie water supplies oti dental caries prevalence tenth year of Grand RapiclsMuskegon study. Public Health Rep. 1956: 71: 652657, 3. BACKER-DIRKS, O . & KWANT, G . W . : A reproducible
method for earies evaluation. Ned. Tijdsclir. Tandheelkd. 19.54: 61: 891-904. 4. Bi-.RNi;Rii, L., FI:KNI:.\-, E . & FIi;i.u, A. J.: A .study on the cariostatic effect of sodium fluoride (Zyniafluor)
naar de gebitsloe.sUind van 6-, 8-, 10- en 12-jarige kiiidercn in Overijssel. Ned. Tijdschr. Tandheelkd. 1976: 83: 290-301, 12. PRKHIAKD, J . E,: The prenatal and irastnatal effeets of fluoride supplements on "West Australian schoolchildren, aged 6", 7 and 8; Perth 1967. Aust. Dent ] 196914: 335-338. 13. STOI.TK, G.: Results of three years of carie.s jjirophylaxis by oral fluoride ap|jlication in Solingen kindergartens, Zahnaerztl. Mitl. 1968: 58; 380-382, 14. STONES, H . H . , EAWTON, F . E , , BRANSUY, E . R . &
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